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1.
IntroductionVibratingobjectsunderwater,suchassubmarineandtorpedo ,transmitnoisetowardsexternalsoundfield ,formachineryvibrationofinsidepowerapparatus.Itwillenhancegreatlytheconcealmentofsubmarineandtorpedoandenforcefightingpowerbycontrollingnoiseofsubma…  相似文献   

2.
The Space-Time Finite Element Method for Parabolic Problems   总被引:1,自引:0,他引:1  
IntroductionTheequationsweconsideredareasfollowsut-Δu =f(u) ,  Ω× [0 ,T] ,u| Ω =0 ,      Ω× [0 ,T] ,u( · ,0 ) =u0 ,Ω ,( 1 )whereΩ ∈R2 ,thefunctionf(u)satisfies|f(u)|≤c|u| ,   u∈C(Ω) . ( 2 )Andf(u)isLipschitzcontinuous,i.e.itsatisfies|f(u) -f(v) |≤L|u-v| ,   u ,v∈C(Ω) ,( 3 )whereLisLipschitzconsta…  相似文献   

3.
IntroductionThefastdiffusionequationofdivergenceformasut =(a(u)ux) x b(u) x c(u)   (a( 0 ) = ∞ ) ( 1 )hasimportantphysicalbackground ,suchas [1 ] .Inrecentyears ,someresultsabout ( 1 )havebeenobtained .Forexample ,[2 ] ,[3]respectivelydiscussedtheCauchyproblemsforequation( 1 )andut=(…  相似文献   

4.
IntroductionThetermhybridisusedtodescribecompositescontainingtwoormoretypesoffibersinacommonmatrix .Hybridcompositeshaveseveraladvantagesascomparedwiththosefabricatedwithasinglefibertype .Thereforenowtheyhavebeenwidelyusedinmanyfieldssuchasaeronauticsa…  相似文献   

5.
IntroductionWeoftenmeettheproblemofsolvingequationofparabolictypeinmanyfieldssuchasseepage ,diffusion ,heatconductionandsoon .Inthecaseof3_dimension ,themodelisaninitialandboundaryvalueproblemasfollows: u t = 2 u x2 2 u y2 2 u z2      (0 <x,y,z<1 ;t>0 ) ,u(x ,y,z,0 ) =φ(x ,y ,z)…  相似文献   

6.
IntroductionOnekindofsteadystatereaction_diffusionequationsisreadas([1,2],etc),F(u,μ)=u″ μ(u-uk)=0(1)withboundaryvalueconditionu(0)=u(π)=0,(2)whereμisaparameter,1<k∈Z .LetX=u∈C2[0,π]|u(0)=u(π)=0,Y=C0[0,π].ThenF(u,μ)isamapfromX×RontoY.Wedefineinnerproductsonthesespacesby〈u,v〉=∫π0u(ξ)v(…  相似文献   

7.
Therearemanydocumentsthatdiscussblow_upofthesolutionsfortheinitial_boundaryvlueproblemsofthenonlinearSchr dingerequations,suchaspaper [1 ] .Butthepaper [1 ]hasoneweakpoint,thatis,itcannotunitediscussionforblow_upofthesolutionsfortheinitial_boundaryvalueprobl…  相似文献   

8.
IntroductionConsidertheperiodicboundaryvalueproblemoftheordinarydifferentialequationsLu≡u″(t) +gradG(u) =p(t) ,u( 0 ) =u( 2π) ,u′( 0 ) =u′( 2π) ,( 1 )wherep∈C(R ,Rn) ,G ∈C2 (Rn,R) .TheequationmaybeinterpretedastheNewtonianequationofmotionofthemechanicalsystemsubjecttoconservati…  相似文献   

9.
IntroductionSoundradiationfromthedoubleshellswhicharethemainstructureofsubmarinehullsunderexcitationinfluidmediumisveryimportantforstudyingthesubmarinehidingtechnology .Forthevibrationcharacteristicofdoubleconcentricshells,ithasbeenstudiedontheoryande…  相似文献   

10.
KINEMATIC WAVE PROPERTIES OF ANISOTROPIC DYNAMICS MODEL FOR TRAFFIC FLOW   总被引:1,自引:0,他引:1  
IntroductionRecentlytheauthorspresentedanewdynamicsmodelfortrafficflow[1].Themodelcomprisesacontinuumequationandadynamicsequation k/ t+ (ku) / x=0 ,( 1 ) u t+u u x=ue(k) -uT +a u x,( 2 )wherekistrafficdensity ;uismeanspeed ;x ,tarespaceandtimecoordinatesrespectively .Tisrel…  相似文献   

11.
Consideringthehigherdimensionalperiodicsystemswithdelayoftheformx′(t)=A(t,x(t))x(t)+f(t,x(t-τ)),(1)x′(t)=gradG(x(t))+f(t,x(t-...  相似文献   

12.
In this paper we begin a study of the differential-delay equation
  相似文献   

13.
We establish new properties of C 1 [τ(1), + ∞)-solutions of the quasilinear functional differential equation
in the neighborhood of the singular point t = +∞.__________Translated from Neliniini Kolyvannya, Vol. 8, No. 1, pp. 3–8, January–March, 2005.  相似文献   

14.
IntroductionIntherecentyears,withalotofapplicationsofneuralnetworkmodels,manyauthors[1~3]areinterestedintheresearchofthestructureandperformanceforthesenetworks.BecauseHopfieldneuralnetworkwellsimulatetheecologicalsystem,manystudiesareconcentratedonth…  相似文献   

15.
We investigate the asymptotic behavior of solutions of the damped nonlinear oscillator equation
where uf(u) > 0 for u ≠ 0, a(t) ≥ 0, and α is a positive constant with 0 < α ≥ 1. The case α = 1 has been investigated by a number of other authors. Here, it is shown that the behavior of solutions in the case of sublinear damping (0 < α < 1) is completely different from that in the case of linear damping (α = 1). Sufficient conditions for all nonoscillatory solutions to converge to zero and sufficient conditions for the existence of a nonoscillatory solution that does not converge to zero are given. We also give sufficient conditions for all solutions to be nonoscillatory. Some open problems for future research are also indicated. __________ Published in Neliniini Kolyvannya, Vol. 8, No. 2, pp. 186–200, April–June, 2005.  相似文献   

16.
The article deals with positive solutions of the Dirichlet problem for
where f(s)>0 for s>0 and f(0)=0. The asymptotic behavior of solutions is discussed for a rather large class of g. For g regular near zero, stability properties of equilibria are investigated.  相似文献   

17.
I.IntroductionItiswell-knobal.nthatKorteweg-deVriesequationisacanonicalmodeltodescribethebalanceofthenonlineareffectandthedispersiveeffectofaphysicalsystem.Thisequationpossessestheso-called'soliton"solution,whichhasbeenfoundnumericallybyZabuskyandKruskall'].Ho-c'Jlever,sometimesthebalanceofnonlinearityanddispersionofasystemmayleadtoa,integroditTerentialequationinsteadofadifferentialequation.Forinstance,inthestudyofvortexbreakdownofanunboundedrotatingfluidLeibovich12]derivedfollowingnonline…  相似文献   

18.
We prove the following statement: Theorem 1. Let E and be an arbitrary infinite-dimensional Banach space and a continuous mapping, respectively. Then, for every and > 0, there exists a continuous mapping such that
and the Cauchy problem
does not have a solution for every > 0.  相似文献   

19.
This paper deals with connected branches of nonstationary periodic trajectories of Hamilton equations
emanating from the degenerate stationary point for H being the generalized Hénon-Heiles (HH) Hamiltonian:
or the generalized Yang-Mills (YM) Hamiltonian:
The existence of such branches has been proved. Minimal periods of searched trajectories near x0 have been described.  相似文献   

20.
We consider the Cauchy problem , x(0) = 0, where a 000 = 0, a 001 = 0, and a 002 = 0, and prove the existence of continuously differentiable solutions x(0,] with required asymptotic properties.  相似文献   

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